1. Field of the Invention
This invention relates to a vehicle and a vehicle substructure for stabilizing a flow of fluid under the floor of a car body.
2. Description of the Related Art
Without any aerodynamic equipment provided under the floor of a car body, a flow of air under the floor of the car body cannot be stabilized and therefore cannot be diffused smoothly at a rear end of the vehicle. Consequently, stability of the vehicle is deteriorated and air resistance increases. For this reason, there exists a sports car provided with a diffuser at a rear end part of the floor of the car body and with a rectifying fin on a flat plate of the diffuser. Furthermore, in the structure described in Japanese Utility Model Application Publication No. 3-103882 (JP-U-3-103882), an under spoiler is provided horizontally in a lower position of a rear bumper that has a predetermined ventilation gap.
However, in the diffuser and the rectifying fin provided on the flat plate, not much change in the flow of air is observed and it is difficult to obtain a sufficiently stabilized air flow. Moreover, when forming the ventilation gap in the lower part of the rear bumper to provide the under spoiler, a certain ground clearance needs to be provided, which affects the departure angle. Therefore, the above-described structure cannot be adopted in a general automobile easily, as it is complicated and increases the air resistance.